Yesterday I found a preliminary report issued on 19th Nov by Norwegian AIB. It describes incident on a B738 in Finland. During intermediate approach horizontal stabilizer moved to position full nose up, a/c pitched up +38,5 deg, KTAS dropped to 118. Fortunately crew was able to recover.
During investigation it has been found that at certain conditions de-icing fluid can ingress into tail cone compartment and it is possible that it freezes, blicking PCU input arms. This concerns all B737.
Abovementioned report:
http://www.aibn.no/Luftfart/Rapporte...-File&attach=1